The ruling engines and diffraction gratings of Henry Augustus Rowland.

During a visit to Europe in the autumn of 1882, Henry Augustus Rowland, Professor of Physics at Johns Hopkins University, displayed diffraction gratings produced on a ruling engine he had designed and built, which were bigger and much higher quality than any previously made. Some were of a novel type, ruled on concave surfaces, which he used in a simple but equally novel spectroscope that he had devised, to reveal spectral lines in great detail, and by means of photography to record spectral data much more rapidly than previously possible. Over about twenty years Rowland built three ruling engines, published photographic maps of the solar spectrum, compiled a catalogue of the wavelengths of lines in the solar spectrum correlated with laboratory-produced spectra of almost all the chemical elements, and produced and sold the diffraction gratings used by spectroscopists everywhere. For decades after his death Rowland's ruling engines remained practically the only source of good-quality diffraction gratings. This paper describes and analyses this work of Rowland and of the other men, Theodore Schneider, John Brashear, and Lewis Jewell, who played major roles in it.

The asymmetry of antimatter in the proton.

The fundamental building blocks of the proton-quarks and gluons-have been known for decades. However, we still have an incomplete theoretical and experimental understanding of how these particles and their dynamics give rise to the quantum bound state of the proton and its physical properties, such as its spin1. The two up quarks and the single down quark that comprise the proton in the simplest picture account only for a few per cent of the proton mass, the bulk of which is in the form of quark kinetic and potential energy and gluon energy from the strong force2. An essential feature of this force, as described by quantum chromodynamics, is its ability to create matter-antimatter quark pairs inside the proton that exist only for a very short time. Their fleeting existence makes the antimatter quarks within protons difficult to study, but their existence is discernible in reactions in which a matter-antimatter quark pair annihilates. In this picture of quark-antiquark creation by the strong force, the probability distributions as a function of momentum for the presence of up and down antimatter quarks should be nearly identical, given that their masses are very similar and small compared to the mass of the proton3. Here we provide evidence from muon pair production measurements that these distributions are considerably different, with more abundant down antimatter quarks than up antimatter quarks over a wide range of momenta. These results are expected to revive interest in several proposed mechanisms for the origin of this antimatter asymmetry in the proton that had been disfavoured by previous results4, and point to future measurements that can distinguish between these mechanisms.

Ruling engines and diffraction gratings before Rowland: the work of Lewis Rutherfurd and William Rogers.

Diffraction gratings are famously associated with Henry Rowland of Johns Hopkins University but there were precursors. Although gratings were first made and used in Europe, reliable machines for ruling gratings were developed in the USA, and two men, Lewis Rutherfurd and William Rogers, tackled the problem before Rowland. Rutherfurd, a wealthy independent astronomer, designed and built the first screw-operated engine for ruling diffraction gratings, the fore-runner of almost all subsequent ruling engines. With it he and his assistant D. C. Chapman ruled many gratings which he generously distributed to practising scientists, thereby materially advancing the science of spectroscopy. Rogers was a Harvard astronomer who developed an interest in the ruling of fine lines on glass that led him to construct a ruling engine with which he investigated the causes of the errors in the rulings he had examined. He continued to seek improvements with a second engine designed for ruling diffraction gratings. He ceased developing this engine when Rowland's excellent gratings began to be available, concentrating instead on related problems to which he could apply the knowledge and skills he had gained, but his investigations assisted Rowland and other later ruling engine builders. This paper brings together what is known about the ruling engines of Rutherfurd and Rogers, their development, the gratings they produced, their quality and the work that was done with them, and assesses and compares their achievements and the impacts of the work of these two men.

Variability in prescription opioid intake and reinforcement amongst 129 substrains.

Opioid abuse in the United States has reached epidemic proportions, with treatment admissions and deaths associated with prescription opioid abuse quadrupling over the past 10 years. Although genetics are theorized to contribute substantially to inter-individual variability in the development, severity and treatment outcomes of opioid abuse/addiction, little direct preclinical study has focused on the behavioral genetics of prescription opioid reinforcement and drug-taking. Herein, we employed different 129 substrains of mice currently available from The Jackson Laboratory (129S1/SvlmJ, 129X1/SvJ, 129S4/SvJaeJ and 129P3/J) as a model system of genetic variation and assayed mice for oral opioid intake and reinforcement, as well as behavioral and somatic signs of dependence. All substrains exhibited a dose-dependent increase in oral oxycodone and heroin preference and intake under limited-access procedures and all, but 129S1/SvlmJ mice, exhibited oxycodone reinforcement. Relative to the other substrains, 129P3/J mice exhibited higher heroin and oxycodone intake. While 129X1/SvJ exhibited the highest anxiety-like behavior during natural opioid withdrawal, somatic and behavior signs of precipitated withdrawal were most robust in 129P3/J mice. These results demonstrate the feasibility and relative sensitivity of our oral opioid self-administration procedures for detecting substrain differences in drug reinforcement/intake among 129 mice, of relevance to the identification of genetic variants contributing to high vs. low oxycodone reinforcement and intake.

Ruling Engines, Diffraction Gratings and Wavelength Measurements before the Rowland Era.

Diffraction gratings have contributed enormously to modern science. Although some historians have written about them, there is much more to be brought to light. This paper discusses their development and use in the period up to about 1880 before Rowland began to produce them. Rittenhouse described the action of a diffraction grating in 1786, but no explanation was possible until the wave theory of light was developed. Fraunhofer discovered the dark lines in the solar spectrum in 1814, and then investigated diffraction, producing the first ruled gratings, making detailed measurements and calculating the wavelengths of prominent spectral lines. After Bunsen and Kirchhoff showed the association between spectral lines and chemical elements there was an upsurge of interest in measuring wavelengths. The gratings used in this work almost all came from one source, a relatively unknown instrument maker called Nobert, who made them by an extremely laborious process using a machine he had built himself. The most significant wavelength measurements were made by Ångström, but Mascart, Van der Willigen, Stefan, Ditscheiner and Cornu also did important work. Nobert gratings were investigated by Quincke, copied photographically by Rayleigh, and were known and discussed in the USA. Nobert's work helped to advance spectroscopy much more than has been acknowledged.

Diagnostic accuracy of instrumented and manual talar tilt tests in chronic ankle instability populations.

Diagnostic accuracy of the talar tilt test is not well established in a chronic ankle instability (CAI) population. Our purpose was to determine the diagnostic accuracy of instrumented and manual talar tilt tests in a group with varied ankle injury history compared with a reference standard of self-report questionnaire. Ninety-three individuals participated, with analysis occurring on 88 (39 CAI, 17 ankle sprain copers, and 32 healthy controls). Participants completed the Cumberland Ankle Instability Tool, arthrometer inversion talar tilt tests (LTT), and manual medial talar tilt stress tests (MTT). The ability to determine CAI status using the LTT and MTT compared with a reference standard was performed. The sensitivity (95% confidence intervals) of LTT and MTT was low [LTT = 0.36 (0.23-0.52), MTT = 0.49 (0.34-0.64)]. Specificity was good to excellent (LTT: 0.72-0.94; MTT: 0.78-0.88). Positive likelihood ratio (+ LR) values for LTT were 1.26-6.10 and for MTT were 2.23-4.14. Negative LR for LTT were 0.68-0.89 and for MTT were 0.58-0.66. Diagnostic odds ratios ranged from 1.43 to 8.96. Both clinical and arthrometer laxity testing appear to have poor overall diagnostic value for evaluating CAI as stand-alone measures. Laxity testing to assess CAI may only be useful to rule in the condition.

Is use of a Continuous Autotransfusion System beneficial in emergency abdominal aortic aneursym (AAA) surgery?

BACKGROUND: Allogeneic blood products have become a limited and expensive resource. The Continuous Autotransfusion System (CATS) has been promoted as a method for reducing the need for allogeneic blood transfusion. This study was undertaken to ascertain whether the use of CATS in emergency open AAA surgery has any benefits. METHODS: This is a retrospective study of all patients undergoing emergency open AAA surgery in our center during a 5-year period (between July 2004 and July 2009). Patients were identified from a prospectively maintained vascular database, and data were obtained from patient records. RESULTS: CATS was used in 69 emergency open AAA repairs. The median total blood loss was 3,500 mL (range: 751-13,796 mL) but the median volume of packed red blood cells produced by CATS was only 493 mL (~ 2 U). An average of 7 U (range: 0-19 U) of bank blood was still used despite the availability of CATS. The mean hemoglobin 24 hours postoperatively was 10.3 g/dL (6.4-14.1) with a hematocrit of 0.30. CONCLUSION: The use of CATS in emergency AAA surgery does not seem to reduce the use of allogeneic blood transfusion. This may be because of over transfusion, as reflected by relatively high postoperative hemoglobin levels.

Invasive group A streptococcal infection: an update on the epidemiology and orthopaedic management.

Invasive group A streptococcus (iGAS) is the most common cause of monomicrobial necrotising fasciitis. Necrotising infections of the extremities may present directly to orthopaedic surgeons or by reference from another admitting specialty. Recent epidemiological data from the Health Protection Agency suggest an increasing incidence of iGAS infection in England. Almost 40% of those affected had no predisposing illnesses or risk factors, and the proportion of children presenting with infections has risen. These observations have prompted the Chief Medical Officer for the Central Alerting System in England to write to general practitioners and hospitals, highlighting the need for clinical vigilance, early diagnosis and rapid initiation of treatment in suspected cases. The purpose of this annotation is to summarise the recent epidemiological trends, describe the presenting features and outline the current investigations and treatment of this rare but life-threatening condition.

Which mesh for hernia repair?

INTRODUCTION: The concept of using a mesh to repair hernias was introduced over 50 years ago. Mesh repair is now standard in most countries and widely accepted as superior to primary suture repair. As a result, there has been a rapid growth in the variety of meshes available and choosing the appropriate one can be difficult. This article outlines the general properties of meshes and factors to be considered when selecting one. MATERIALS AND METHODS: We performed a search of the medical literature from 1950 to 1 May 2009, as indexed by Medline, using the PubMed search engine (www.pubmed.gov). To capture all potentially relevant articles with the highest degree of sensitivity, the search terms were intentionally broad. We used the following terms: 'mesh, pore size, strength, recurrence, complications, lightweight, properties'. We also hand-searched the bibliographies of relevant articles and product literature to identify additional pertinent reports. RESULTS AND CONCLUSIONS: The most important properties of meshes were found to be the type of filament, tensile strength and porosity. These determine the weight of the mesh and its biocompatibility. The tensile strength required is much less than originally presumed and light-weight meshes are thought to be superior due to their increased flexibility and reduction in discomfort. Large pores are also associated with a reduced risk of infection and shrinkage. For meshes placed in the peritoneal cavity, consideration should also be given to the risk of adhesion formation. A variety of composite meshes have been promoted to address this, but none appears superior to the others. Finally, biomaterials such as acellular dermis have a place for use in infected fields but have yet to prove their worth in routine hernia repair.

Measurement of angular distributions of Drell-Yan dimuons in p+p interactions at 800 GeV/c.

We report a measurement of the angular distributions of Drell-Yan dimuons produced using an 800 GeV/c proton beam on a hydrogen target. The polar and azimuthal angular distribution parameters have been extracted over the kinematic range 4.5

The EVAR Trial 1: has it led to a change in practice?

OBJECTIVES: To assess whether the publication of the EVAR Trial 1 (June 2005) had an impact on practice in our centre. METHODS: A retrospective study of all patients undergoing abdominal aortic aneurysm (AAA) repair in Leicester, from the year before publication of EVAR Trial 1 data to the year after (July 2004 - June 2006). Data from the study period was then compared with practice over the last six years (January 2000 - December 2006). RESULTS: The proportion of endovascular aneurysm repairs (EVARs) did not change significantly in the year following publication of EVAR Trial 1 data (52% VS 57%, p=0.64). The mean age of patients offered open repair (OR) fell in the year following publication (69 years +/- 6.68 vs 72 years +/- 5.71, p<0.05). Despite this, there was no significant change in their fitness (physiological POSSUM scores: 19.2 +/- 3.91 vs 18.2 +/- 3.74, P=0.30). There was an overall increase in the percentage of EVARs in the years 2000 (28%) to 2006 (57%). CONCLUSION: There was no significant difference in the percentage of EVARs between the two years of study. However, over the last six years, there has been an increasing number performed in our unit and we now do more EVARs than ORs.

Measurement of Upsilon production for p + p and p + d interactions at 800 GeV/c.

We report a high statistics measurement of Upsilon production with an 800 GeV/c proton beam on hydrogen and deuterium targets. The dominance of the gluon-gluon fusion process for Upsilon production at this energy implies that the cross section ratio, sigma(p+d-->Upsilon)/2sigma(p+p-->Upsilon), is sensitive to the gluon content in the neutron relative to that in the proton. Over the kinematic region 0

Measurement of angular distributions of Drell-Yan dimuons in p+d interactions at 800 GeV/c.

We report a measurement of the angular distributions of Drell-Yan dimuons produced using an 800 GeV/c proton beam on a deuterium target. The muon angular distributions in the dilepton rest frame have been measured over the kinematic range 4.5

J/psi polarization in 800-GeV p-Cu interactions.

We present measurements of the polarization of the J/psi produced in 800-GeV proton interactions with a copper target. Polarization of the J/psi is sensitive to the ccmacr; production and hadronization processes. A longitudinal polarization is observed at large x(F), while at small x(F) the state is produced essentially unpolarized or slightly transversely polarized. No significant variation of the polarization is observed versus p(T).

Effects of prolonged reduction in blood flow on submandibular secretory function in anesthetized sheep.

Submandibular vascular and secretory responses to parasympathetic chorda-lingual (C-L) stimulation were investigated in anesthetized sheep before, during, and after an intracarotid (ic) infusion of endothelin-1 (ET-1). Stimulation of the peripheral end of the C-L nerve at 4 and 8 Hz produced a frequency-dependent reduction in submandibular vascular resistance (SVR) associated with a frequency-dependent increase in submandibular blood flow, salivary flow, and Na+, K+, and protein output from the gland. During stimulation at 4 Hz, ic ET-1 significantly increased SVR (P < 0.01), without significantly affecting either the aortic blood pressure or heart rate. Submandibular blood flow (SBF) was reduced by 48 +/- 4% and the flow of saliva by 50 +/- 1%. The effect on blood and salivary flow persisted for at least 30 min after the infusion of ET-1. The reduction in SBF was associated with a diminution in the output of Na+,K+, and protein in the saliva (P < 0.01). These effects persisted for 30 min after the infusion of ET-1 had been discontinued and were linearly related to the flow of plasma throughout.

Energy loss of fast quarks in nuclei.

We report an analysis of the nuclear dependence of the yield of Drell-Yan dimuons from the 800 GeV/c proton bombardment of 2H, C, Ca, Fe, and W targets. Employing a new formulation of the Drell-Yan process in the rest frame of the nucleus, this analysis examines the effect of initial-state energy loss and shadowing on the nuclear-dependence ratios versus the incident proton's momentum fraction and dimuon effective mass. The resulting energy loss per unit path length is -dE/dz = 2.32+/-0.52+/-0.5 GeV/fm. This is the first observation of a nonzero energy loss of partons traveling in a nuclear environment.

Observation of polarization in bottomonium production at square root of s = 38.8 GeV.

We present a measurement of the polarization observed for bottomonium states produced in p-Cu collisions at square root of s = 38.8 GeV. The angular distribution of the decay dimuons of the Upsilon(1S) state shows no polarization at small values of the fractional longitudinal momentum x(F) and transverse momentum p(T) but significant positive transverse production polarization for either p(T)>1.8 GeV/c or for x(F)>0.35. The Upsilon(2S+3S) (unresolved) states show a large transverse production polarization at all values of x(F) and p(T) measured. These observations challenge NRQCD calculations of the polarization expected in the hadronic production of bottomonium states.

Identification of transient and persistent segmental wall motion abnormalities in patients with unstable angina by two-dimensional echocardiography.

To determine the value of real-time, two-dimensional echocardiography (2-D echo) in unstable angina, regional wall motion on serial short-axis 2-D echo recordings was analyzed and summed segment scores of abnormal motion were compared and classified according to each patient's clinical status 12 weeks after hospital discharge. Nineteen male patients who fulfilled criteria for unstable angina and responded to medical therapy underwent 2-D echo study within 48 hours of admission and discharge. Of 11 patients with abnormal 2-D echo scores on admission, five patients had reduced scores and six patients had similar or increased scores at discharge. Six of eight patients who had scores of zero on admission had scores of zero at discharge. At follow-up, 11 patients had minimal or no angina pectoris (group 1), and eight patients had worsening angina or recurrent unstable angina (group 2). At discharge, 2-D echo studies showed that all group 1 patients had reduced or zero scores, while group 2 patients retained or increased their abnormal scores. This study shows that in patients with unstable angina, both transient and persistent abnormalities can be identified by 2-D echo. Abnormal segmental wall motion was transient or absent in patients with a good outcome, and worsened or remained abnormal in patients with a poor outcome.